Mercurial > hg > graal-compiler
annotate src/share/vm/code/dependencies.hpp @ 1123:167c2986d91b
6843629: Make current hotspot build part of jdk5 control build
Summary: Source changes for older compilers plus makefile changes.
Reviewed-by: xlu
| author | phh |
|---|---|
| date | Wed, 16 Dec 2009 12:54:49 -0500 |
| parents | a61af66fc99e |
| children | c18cbe5936b8 |
| rev | line source |
|---|---|
| 0 | 1 /* |
| 2 * Copyright 2005-2006 Sun Microsystems, Inc. All Rights Reserved. | |
| 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. | |
| 4 * | |
| 5 * This code is free software; you can redistribute it and/or modify it | |
| 6 * under the terms of the GNU General Public License version 2 only, as | |
| 7 * published by the Free Software Foundation. | |
| 8 * | |
| 9 * This code is distributed in the hope that it will be useful, but WITHOUT | |
| 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
| 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
| 12 * version 2 for more details (a copy is included in the LICENSE file that | |
| 13 * accompanied this code). | |
| 14 * | |
| 15 * You should have received a copy of the GNU General Public License version | |
| 16 * 2 along with this work; if not, write to the Free Software Foundation, | |
| 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. | |
| 18 * | |
| 19 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, | |
| 20 * CA 95054 USA or visit www.sun.com if you need additional information or | |
| 21 * have any questions. | |
| 22 * | |
| 23 */ | |
| 24 | |
| 25 //** Dependencies represent assertions (approximate invariants) within | |
| 26 // the class hierarchy. An example is an assertion that a given | |
| 27 // method is not overridden; another example is that a type has only | |
| 28 // one concrete subtype. Compiled code which relies on such | |
| 29 // assertions must be discarded if they are overturned by changes in | |
| 30 // the class hierarchy. We can think of these assertions as | |
| 31 // approximate invariants, because we expect them to be overturned | |
| 32 // very infrequently. We are willing to perform expensive recovery | |
| 33 // operations when they are overturned. The benefit, of course, is | |
| 34 // performing optimistic optimizations (!) on the object code. | |
| 35 // | |
| 36 // Changes in the class hierarchy due to dynamic linking or | |
| 37 // class evolution can violate dependencies. There is enough | |
| 38 // indexing between classes and nmethods to make dependency | |
| 39 // checking reasonably efficient. | |
| 40 | |
| 41 class ciEnv; | |
| 42 class nmethod; | |
| 43 class OopRecorder; | |
| 44 class xmlStream; | |
| 45 class CompileLog; | |
| 46 class DepChange; | |
| 47 class No_Safepoint_Verifier; | |
| 48 | |
| 49 class Dependencies: public ResourceObj { | |
| 50 public: | |
| 51 // Note: In the comments on dependency types, most uses of the terms | |
| 52 // subtype and supertype are used in a "non-strict" or "inclusive" | |
| 53 // sense, and are starred to remind the reader of this fact. | |
| 54 // Strict uses of the terms use the word "proper". | |
| 55 // | |
| 56 // Specifically, every class is its own subtype* and supertype*. | |
| 57 // (This trick is easier than continually saying things like "Y is a | |
| 58 // subtype of X or X itself".) | |
| 59 // | |
| 60 // Sometimes we write X > Y to mean X is a proper supertype of Y. | |
| 61 // The notation X > {Y, Z} means X has proper subtypes Y, Z. | |
| 62 // The notation X.m > Y means that Y inherits m from X, while | |
| 63 // X.m > Y.m means Y overrides X.m. A star denotes abstractness, | |
| 64 // as *I > A, meaning (abstract) interface I is a super type of A, | |
| 65 // or A.*m > B.m, meaning B.m implements abstract method A.m. | |
| 66 // | |
| 67 // In this module, the terms "subtype" and "supertype" refer to | |
| 68 // Java-level reference type conversions, as detected by | |
| 69 // "instanceof" and performed by "checkcast" operations. The method | |
| 70 // Klass::is_subtype_of tests these relations. Note that "subtype" | |
| 71 // is richer than "subclass" (as tested by Klass::is_subclass_of), | |
| 72 // since it takes account of relations involving interface and array | |
| 73 // types. | |
| 74 // | |
| 75 // To avoid needless complexity, dependencies involving array types | |
| 76 // are not accepted. If you need to make an assertion about an | |
| 77 // array type, make the assertion about its corresponding element | |
| 78 // types. Any assertion that might change about an array type can | |
| 79 // be converted to an assertion about its element type. | |
| 80 // | |
| 81 // Most dependencies are evaluated over a "context type" CX, which | |
| 82 // stands for the set Subtypes(CX) of every Java type that is a subtype* | |
| 83 // of CX. When the system loads a new class or interface N, it is | |
| 84 // responsible for re-evaluating changed dependencies whose context | |
| 85 // type now includes N, that is, all super types of N. | |
| 86 // | |
| 87 enum DepType { | |
| 88 end_marker = 0, | |
| 89 | |
| 90 // An 'evol' dependency simply notes that the contents of the | |
| 91 // method were used. If it evolves (is replaced), the nmethod | |
| 92 // must be recompiled. No other dependencies are implied. | |
| 93 evol_method, | |
| 94 FIRST_TYPE = evol_method, | |
| 95 | |
| 96 // A context type CX is a leaf it if has no proper subtype. | |
| 97 leaf_type, | |
| 98 | |
| 99 // An abstract class CX has exactly one concrete subtype CC. | |
| 100 abstract_with_unique_concrete_subtype, | |
| 101 | |
| 102 // The type CX is purely abstract, with no concrete subtype* at all. | |
| 103 abstract_with_no_concrete_subtype, | |
| 104 | |
| 105 // The concrete CX is free of concrete proper subtypes. | |
| 106 concrete_with_no_concrete_subtype, | |
| 107 | |
| 108 // Given a method M1 and a context class CX, the set MM(CX, M1) of | |
| 109 // "concrete matching methods" in CX of M1 is the set of every | |
| 110 // concrete M2 for which it is possible to create an invokevirtual | |
| 111 // or invokeinterface call site that can reach either M1 or M2. | |
| 112 // That is, M1 and M2 share a name, signature, and vtable index. | |
| 113 // We wish to notice when the set MM(CX, M1) is just {M1}, or | |
| 114 // perhaps a set of two {M1,M2}, and issue dependencies on this. | |
| 115 | |
| 116 // The set MM(CX, M1) can be computed by starting with any matching | |
| 117 // concrete M2 that is inherited into CX, and then walking the | |
| 118 // subtypes* of CX looking for concrete definitions. | |
| 119 | |
| 120 // The parameters to this dependency are the method M1 and the | |
| 121 // context class CX. M1 must be either inherited in CX or defined | |
| 122 // in a subtype* of CX. It asserts that MM(CX, M1) is no greater | |
| 123 // than {M1}. | |
| 124 unique_concrete_method, // one unique concrete method under CX | |
| 125 | |
| 126 // An "exclusive" assertion concerns two methods or subtypes, and | |
| 127 // declares that there are at most two (or perhaps later N>2) | |
| 128 // specific items that jointly satisfy the restriction. | |
| 129 // We list all items explicitly rather than just giving their | |
| 130 // count, for robustness in the face of complex schema changes. | |
| 131 | |
| 132 // A context class CX (which may be either abstract or concrete) | |
| 133 // has two exclusive concrete subtypes* C1, C2 if every concrete | |
| 134 // subtype* of CX is either C1 or C2. Note that if neither C1 or C2 | |
| 135 // are equal to CX, then CX itself must be abstract. But it is | |
| 136 // also possible (for example) that C1 is CX (a concrete class) | |
| 137 // and C2 is a proper subtype of C1. | |
| 138 abstract_with_exclusive_concrete_subtypes_2, | |
| 139 | |
| 140 // This dependency asserts that MM(CX, M1) is no greater than {M1,M2}. | |
| 141 exclusive_concrete_methods_2, | |
| 142 | |
| 143 // This dependency asserts that no instances of class or it's | |
| 144 // subclasses require finalization registration. | |
| 145 no_finalizable_subclasses, | |
| 146 | |
| 147 TYPE_LIMIT | |
| 148 }; | |
| 149 enum { | |
| 150 LG2_TYPE_LIMIT = 4, // assert(TYPE_LIMIT <= (1<<LG2_TYPE_LIMIT)) | |
| 151 | |
| 152 // handy categorizations of dependency types: | |
| 153 all_types = ((1<<TYPE_LIMIT)-1) & ((-1)<<FIRST_TYPE), | |
| 154 non_ctxk_types = (1<<evol_method), | |
| 155 ctxk_types = all_types & ~non_ctxk_types, | |
| 156 | |
| 157 max_arg_count = 3, // current maximum number of arguments (incl. ctxk) | |
| 158 | |
| 159 // A "context type" is a class or interface that | |
| 160 // provides context for evaluating a dependency. | |
| 161 // When present, it is one of the arguments (dep_context_arg). | |
| 162 // | |
| 163 // If a dependency does not have a context type, there is a | |
| 164 // default context, depending on the type of the dependency. | |
| 165 // This bit signals that a default context has been compressed away. | |
| 166 default_context_type_bit = (1<<LG2_TYPE_LIMIT) | |
| 167 }; | |
| 168 | |
| 169 static const char* dep_name(DepType dept); | |
| 170 static int dep_args(DepType dept); | |
| 171 static int dep_context_arg(DepType dept) { | |
| 172 return dept_in_mask(dept, ctxk_types)? 0: -1; | |
| 173 } | |
| 174 | |
| 175 private: | |
| 176 // State for writing a new set of dependencies: | |
| 177 GrowableArray<int>* _dep_seen; // (seen[h->ident] & (1<<dept)) | |
| 178 GrowableArray<ciObject*>* _deps[TYPE_LIMIT]; | |
| 179 | |
| 180 static const char* _dep_name[TYPE_LIMIT]; | |
| 181 static int _dep_args[TYPE_LIMIT]; | |
| 182 | |
| 183 static bool dept_in_mask(DepType dept, int mask) { | |
| 184 return (int)dept >= 0 && dept < TYPE_LIMIT && ((1<<dept) & mask) != 0; | |
| 185 } | |
| 186 | |
| 187 bool note_dep_seen(int dept, ciObject* x) { | |
| 188 assert(dept < BitsPerInt, "oob"); | |
| 189 int x_id = x->ident(); | |
| 190 assert(_dep_seen != NULL, "deps must be writable"); | |
| 191 int seen = _dep_seen->at_grow(x_id, 0); | |
| 192 _dep_seen->at_put(x_id, seen | (1<<dept)); | |
| 193 // return true if we've already seen dept/x | |
| 194 return (seen & (1<<dept)) != 0; | |
| 195 } | |
| 196 | |
| 197 bool maybe_merge_ctxk(GrowableArray<ciObject*>* deps, | |
| 198 int ctxk_i, ciKlass* ctxk); | |
| 199 | |
| 200 void sort_all_deps(); | |
| 201 size_t estimate_size_in_bytes(); | |
| 202 | |
| 203 // Initialize _deps, etc. | |
| 204 void initialize(ciEnv* env); | |
| 205 | |
| 206 // State for making a new set of dependencies: | |
| 207 OopRecorder* _oop_recorder; | |
| 208 | |
| 209 // Logging support | |
| 210 CompileLog* _log; | |
| 211 | |
| 212 address _content_bytes; // everything but the oop references, encoded | |
| 213 size_t _size_in_bytes; | |
| 214 | |
| 215 public: | |
| 216 // Make a new empty dependencies set. | |
| 217 Dependencies(ciEnv* env) { | |
| 218 initialize(env); | |
| 219 } | |
| 220 | |
| 221 private: | |
| 222 // Check for a valid context type. | |
| 223 // Enforce the restriction against array types. | |
| 224 static void check_ctxk(ciKlass* ctxk) { | |
| 225 assert(ctxk->is_instance_klass(), "java types only"); | |
| 226 } | |
| 227 static void check_ctxk_concrete(ciKlass* ctxk) { | |
| 228 assert(is_concrete_klass(ctxk->as_instance_klass()), "must be concrete"); | |
| 229 } | |
| 230 static void check_ctxk_abstract(ciKlass* ctxk) { | |
| 231 check_ctxk(ctxk); | |
| 232 assert(!is_concrete_klass(ctxk->as_instance_klass()), "must be abstract"); | |
| 233 } | |
| 234 | |
| 235 void assert_common_1(DepType dept, ciObject* x); | |
| 236 void assert_common_2(DepType dept, ciKlass* ctxk, ciObject* x); | |
| 237 void assert_common_3(DepType dept, ciKlass* ctxk, ciObject* x, ciObject* x2); | |
| 238 | |
| 239 public: | |
| 240 // Adding assertions to a new dependency set at compile time: | |
| 241 void assert_evol_method(ciMethod* m); | |
| 242 void assert_leaf_type(ciKlass* ctxk); | |
| 243 void assert_abstract_with_unique_concrete_subtype(ciKlass* ctxk, ciKlass* conck); | |
| 244 void assert_abstract_with_no_concrete_subtype(ciKlass* ctxk); | |
| 245 void assert_concrete_with_no_concrete_subtype(ciKlass* ctxk); | |
| 246 void assert_unique_concrete_method(ciKlass* ctxk, ciMethod* uniqm); | |
| 247 void assert_abstract_with_exclusive_concrete_subtypes(ciKlass* ctxk, ciKlass* k1, ciKlass* k2); | |
| 248 void assert_exclusive_concrete_methods(ciKlass* ctxk, ciMethod* m1, ciMethod* m2); | |
| 249 void assert_has_no_finalizable_subclasses(ciKlass* ctxk); | |
| 250 | |
| 251 // Define whether a given method or type is concrete. | |
| 252 // These methods define the term "concrete" as used in this module. | |
| 253 // For this module, an "abstract" class is one which is non-concrete. | |
| 254 // | |
| 255 // Future optimizations may allow some classes to remain | |
| 256 // non-concrete until their first instantiation, and allow some | |
| 257 // methods to remain non-concrete until their first invocation. | |
| 258 // In that case, there would be a middle ground between concrete | |
| 259 // and abstract (as defined by the Java language and VM). | |
| 260 static bool is_concrete_klass(klassOop k); // k is instantiable | |
| 261 static bool is_concrete_method(methodOop m); // m is invocable | |
| 262 static Klass* find_finalizable_subclass(Klass* k); | |
| 263 | |
| 264 // These versions of the concreteness queries work through the CI. | |
| 265 // The CI versions are allowed to skew sometimes from the VM | |
| 266 // (oop-based) versions. The cost of such a difference is a | |
| 267 // (safely) aborted compilation, or a deoptimization, or a missed | |
| 268 // optimization opportunity. | |
| 269 // | |
| 270 // In order to prevent spurious assertions, query results must | |
| 271 // remain stable within any single ciEnv instance. (I.e., they must | |
| 272 // not go back into the VM to get their value; they must cache the | |
| 273 // bit in the CI, either eagerly or lazily.) | |
| 274 static bool is_concrete_klass(ciInstanceKlass* k); // k appears instantiable | |
| 275 static bool is_concrete_method(ciMethod* m); // m appears invocable | |
| 276 static bool has_finalizable_subclass(ciInstanceKlass* k); | |
| 277 | |
| 278 // As a general rule, it is OK to compile under the assumption that | |
| 279 // a given type or method is concrete, even if it at some future | |
| 280 // point becomes abstract. So dependency checking is one-sided, in | |
| 281 // that it permits supposedly concrete classes or methods to turn up | |
| 282 // as really abstract. (This shouldn't happen, except during class | |
| 283 // evolution, but that's the logic of the checking.) However, if a | |
| 284 // supposedly abstract class or method suddenly becomes concrete, a | |
| 285 // dependency on it must fail. | |
| 286 | |
| 287 // Checking old assertions at run-time (in the VM only): | |
| 288 static klassOop check_evol_method(methodOop m); | |
| 289 static klassOop check_leaf_type(klassOop ctxk); | |
| 290 static klassOop check_abstract_with_unique_concrete_subtype(klassOop ctxk, klassOop conck, | |
| 291 DepChange* changes = NULL); | |
| 292 static klassOop check_abstract_with_no_concrete_subtype(klassOop ctxk, | |
| 293 DepChange* changes = NULL); | |
| 294 static klassOop check_concrete_with_no_concrete_subtype(klassOop ctxk, | |
| 295 DepChange* changes = NULL); | |
| 296 static klassOop check_unique_concrete_method(klassOop ctxk, methodOop uniqm, | |
| 297 DepChange* changes = NULL); | |
| 298 static klassOop check_abstract_with_exclusive_concrete_subtypes(klassOop ctxk, klassOop k1, klassOop k2, | |
| 299 DepChange* changes = NULL); | |
| 300 static klassOop check_exclusive_concrete_methods(klassOop ctxk, methodOop m1, methodOop m2, | |
| 301 DepChange* changes = NULL); | |
| 302 static klassOop check_has_no_finalizable_subclasses(klassOop ctxk, | |
| 303 DepChange* changes = NULL); | |
| 304 // A returned klassOop is NULL if the dependency assertion is still | |
| 305 // valid. A non-NULL klassOop is a 'witness' to the assertion | |
| 306 // failure, a point in the class hierarchy where the assertion has | |
| 307 // been proven false. For example, if check_leaf_type returns | |
| 308 // non-NULL, the value is a subtype of the supposed leaf type. This | |
| 309 // witness value may be useful for logging the dependency failure. | |
| 310 // Note that, when a dependency fails, there may be several possible | |
| 311 // witnesses to the failure. The value returned from the check_foo | |
| 312 // method is chosen arbitrarily. | |
| 313 | |
| 314 // The 'changes' value, if non-null, requests a limited spot-check | |
| 315 // near the indicated recent changes in the class hierarchy. | |
| 316 // It is used by DepStream::spot_check_dependency_at. | |
| 317 | |
| 318 // Detecting possible new assertions: | |
| 319 static klassOop find_unique_concrete_subtype(klassOop ctxk); | |
| 320 static methodOop find_unique_concrete_method(klassOop ctxk, methodOop m); | |
| 321 static int find_exclusive_concrete_subtypes(klassOop ctxk, int klen, klassOop k[]); | |
| 322 static int find_exclusive_concrete_methods(klassOop ctxk, int mlen, methodOop m[]); | |
| 323 | |
| 324 // Create the encoding which will be stored in an nmethod. | |
| 325 void encode_content_bytes(); | |
| 326 | |
| 327 address content_bytes() { | |
| 328 assert(_content_bytes != NULL, "encode it first"); | |
| 329 return _content_bytes; | |
| 330 } | |
| 331 size_t size_in_bytes() { | |
| 332 assert(_content_bytes != NULL, "encode it first"); | |
| 333 return _size_in_bytes; | |
| 334 } | |
| 335 | |
| 336 OopRecorder* oop_recorder() { return _oop_recorder; } | |
| 337 CompileLog* log() { return _log; } | |
| 338 | |
| 339 void copy_to(nmethod* nm); | |
| 340 | |
| 341 void log_all_dependencies(); | |
| 342 void log_dependency(DepType dept, int nargs, ciObject* args[]) { | |
| 343 write_dependency_to(log(), dept, nargs, args); | |
| 344 } | |
| 345 void log_dependency(DepType dept, | |
| 346 ciObject* x0, | |
| 347 ciObject* x1 = NULL, | |
| 348 ciObject* x2 = NULL) { | |
| 349 if (log() == NULL) return; | |
| 350 ciObject* args[max_arg_count]; | |
| 351 args[0] = x0; | |
| 352 args[1] = x1; | |
| 353 args[2] = x2; | |
| 354 assert(2 < max_arg_count, ""); | |
| 355 log_dependency(dept, dep_args(dept), args); | |
| 356 } | |
| 357 | |
| 358 static void write_dependency_to(CompileLog* log, | |
| 359 DepType dept, | |
| 360 int nargs, ciObject* args[], | |
| 361 klassOop witness = NULL); | |
| 362 static void write_dependency_to(CompileLog* log, | |
| 363 DepType dept, | |
| 364 int nargs, oop args[], | |
| 365 klassOop witness = NULL); | |
| 366 static void write_dependency_to(xmlStream* xtty, | |
| 367 DepType dept, | |
| 368 int nargs, oop args[], | |
| 369 klassOop witness = NULL); | |
| 370 static void print_dependency(DepType dept, | |
| 371 int nargs, oop args[], | |
| 372 klassOop witness = NULL); | |
| 373 | |
| 374 private: | |
| 375 // helper for encoding common context types as zero: | |
| 376 static ciKlass* ctxk_encoded_as_null(DepType dept, ciObject* x); | |
| 377 | |
| 378 static klassOop ctxk_encoded_as_null(DepType dept, oop x); | |
| 379 | |
| 380 public: | |
| 381 // Use this to iterate over an nmethod's dependency set. | |
| 382 // Works on new and old dependency sets. | |
| 383 // Usage: | |
| 384 // | |
| 385 // ; | |
| 386 // Dependencies::DepType dept; | |
| 387 // for (Dependencies::DepStream deps(nm); deps.next(); ) { | |
| 388 // ... | |
| 389 // } | |
| 390 // | |
| 391 // The caller must be in the VM, since oops are not wrapped in handles. | |
| 392 class DepStream { | |
| 393 private: | |
| 394 nmethod* _code; // null if in a compiler thread | |
| 395 Dependencies* _deps; // null if not in a compiler thread | |
| 396 CompressedReadStream _bytes; | |
| 397 #ifdef ASSERT | |
| 398 size_t _byte_limit; | |
| 399 #endif | |
| 400 | |
| 401 // iteration variables: | |
| 402 DepType _type; | |
| 403 int _xi[max_arg_count+1]; | |
| 404 | |
| 405 void initial_asserts(size_t byte_limit) NOT_DEBUG({}); | |
| 406 | |
| 407 inline oop recorded_oop_at(int i); | |
| 408 // => _code? _code->oop_at(i): *_deps->_oop_recorder->handle_at(i) | |
| 409 | |
| 410 klassOop check_dependency_impl(DepChange* changes); | |
| 411 | |
| 412 public: | |
| 413 DepStream(Dependencies* deps) | |
| 414 : _deps(deps), | |
| 415 _code(NULL), | |
| 416 _bytes(deps->content_bytes()) | |
| 417 { | |
| 418 initial_asserts(deps->size_in_bytes()); | |
| 419 } | |
| 420 DepStream(nmethod* code) | |
| 421 : _deps(NULL), | |
| 422 _code(code), | |
| 423 _bytes(code->dependencies_begin()) | |
| 424 { | |
| 425 initial_asserts(code->dependencies_size()); | |
| 426 } | |
| 427 | |
| 428 bool next(); | |
| 429 | |
| 430 DepType type() { return _type; } | |
| 431 int argument_count() { return dep_args(type()); } | |
| 432 int argument_index(int i) { assert(0 <= i && i < argument_count(), "oob"); | |
| 433 return _xi[i]; } | |
| 434 oop argument(int i); // => recorded_oop_at(argument_index(i)) | |
| 435 klassOop context_type(); | |
| 436 | |
| 437 methodOop method_argument(int i) { | |
| 438 oop x = argument(i); | |
| 439 assert(x->is_method(), "type"); | |
| 440 return (methodOop) x; | |
| 441 } | |
| 442 klassOop type_argument(int i) { | |
| 443 oop x = argument(i); | |
| 444 assert(x->is_klass(), "type"); | |
| 445 return (klassOop) x; | |
| 446 } | |
| 447 | |
| 448 // The point of the whole exercise: Is this dep is still OK? | |
| 449 klassOop check_dependency() { | |
| 450 return check_dependency_impl(NULL); | |
| 451 } | |
| 452 // A lighter version: Checks only around recent changes in a class | |
| 453 // hierarchy. (See Universe::flush_dependents_on.) | |
| 454 klassOop spot_check_dependency_at(DepChange& changes); | |
| 455 | |
| 456 // Log the current dependency to xtty or compilation log. | |
| 457 void log_dependency(klassOop witness = NULL); | |
| 458 | |
| 459 // Print the current dependency to tty. | |
| 460 void print_dependency(klassOop witness = NULL, bool verbose = false); | |
| 461 }; | |
| 462 friend class Dependencies::DepStream; | |
| 463 | |
| 464 static void print_statistics() PRODUCT_RETURN; | |
| 465 }; | |
| 466 | |
| 467 // A class hierarchy change coming through the VM (under the Compile_lock). | |
| 468 // The change is structured as a single new type with any number of supers | |
| 469 // and implemented interface types. Other than the new type, any of the | |
| 470 // super types can be context types for a relevant dependency, which the | |
| 471 // new type could invalidate. | |
| 472 class DepChange : public StackObj { | |
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473 public: |
| 0 | 474 enum ChangeType { |
| 475 NO_CHANGE = 0, // an uninvolved klass | |
| 476 Change_new_type, // a newly loaded type | |
| 477 Change_new_sub, // a super with a new subtype | |
| 478 Change_new_impl, // an interface with a new implementation | |
| 479 CHANGE_LIMIT, | |
| 480 Start_Klass = CHANGE_LIMIT // internal indicator for ContextStream | |
| 481 }; | |
| 482 | |
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483 private: |
| 0 | 484 // each change set is rooted in exactly one new type (at present): |
| 485 KlassHandle _new_type; | |
| 486 | |
| 487 void initialize(); | |
| 488 | |
| 489 public: | |
| 490 // notes the new type, marks it and all its super-types | |
| 491 DepChange(KlassHandle new_type) | |
| 492 : _new_type(new_type) | |
| 493 { | |
| 494 initialize(); | |
| 495 } | |
| 496 | |
| 497 // cleans up the marks | |
| 498 ~DepChange(); | |
| 499 | |
| 500 klassOop new_type() { return _new_type(); } | |
| 501 | |
| 502 // involves_context(k) is true if k is new_type or any of the super types | |
| 503 bool involves_context(klassOop k); | |
| 504 | |
| 505 // Usage: | |
| 506 // for (DepChange::ContextStream str(changes); str.next(); ) { | |
| 507 // klassOop k = str.klass(); | |
| 508 // switch (str.change_type()) { | |
| 509 // ... | |
| 510 // } | |
| 511 // } | |
| 512 class ContextStream : public StackObj { | |
| 513 private: | |
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514 DepChange& _changes; |
| 0 | 515 friend class DepChange; |
| 516 | |
| 517 // iteration variables: | |
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518 ChangeType _change_type; |
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519 klassOop _klass; |
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520 objArrayOop _ti_base; // i.e., transitive_interfaces |
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521 int _ti_index; |
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522 int _ti_limit; |
| 0 | 523 |
| 524 // start at the beginning: | |
| 525 void start() { | |
| 526 klassOop new_type = _changes.new_type(); | |
| 527 _change_type = (new_type == NULL ? NO_CHANGE: Start_Klass); | |
| 528 _klass = new_type; | |
| 529 _ti_base = NULL; | |
| 530 _ti_index = 0; | |
| 531 _ti_limit = 0; | |
| 532 } | |
| 533 | |
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534 public: |
| 0 | 535 ContextStream(DepChange& changes) |
| 536 : _changes(changes) | |
| 537 { start(); } | |
| 538 | |
| 539 ContextStream(DepChange& changes, No_Safepoint_Verifier& nsv) | |
| 540 : _changes(changes) | |
| 541 // the nsv argument makes it safe to hold oops like _klass | |
| 542 { start(); } | |
| 543 | |
| 544 bool next(); | |
| 545 | |
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546 ChangeType change_type() { return _change_type; } |
| 0 | 547 klassOop klass() { return _klass; } |
| 548 }; | |
| 549 friend class DepChange::ContextStream; | |
| 550 | |
| 551 void print(); | |
| 552 }; |